II. THE SOCIO-POLITICAL AND ECONOMIC FRAMEWORK file30 802012 II. THE SOCIO-POLITICAL AND ECONOMIC...

30 DOLENTIUM HOMINUM N. 80-2012

II. THE SOCIO-POLITICAL AND ECONOMIC FRAMEWORK

II.1 Epidemiologia: cecità ed ipovisione nel mondo oggi

DOTT. SILVIO PAOLO MARIOTTI Responsabile del Programma per la Prevenzione della Cecità e Sordità dell’Organizzazione Mondiale della Sanità (OMS)Ginevra, Svizzera

Epidemiology: Blindness and Low Vision in the WorldDr. Silvio Paolo Mariotti, Director of the Programme for the Prevention of Blindness and Deafness of the WHO, describes the estimates for the year 2010, according to which 285 million people in the world have a grave sight deficit. Of these, 246 million have defective vision and 39 million are blind. As regards this deficit, about 80% of cases are treatable and preventable. Compared to the estimates for 2004, the number of people with defective vision and blind people in the world has decreased by 9%. This is the most recent news because investments for prevention made by governments, institutions, agencies for bilateral help, and NGOs have had an important impact. This reduction has been especially noted in the region of Africa where advances in the development of health-care and social systems have been particularly evident.However, the fact remains that a large part of the world’s population suffers every day because of a handicap that could, in 80% of cases, be treated or avoided.The first causes of defective sight in the world are the negative results of uncorrected

refraction (in particular in children), whereas the first cause of blindness is cataract that has not been operated on (prevalent in people over the age of fifty).The fact that an increasing number of countries have successfully eliminated pathologies that cause blindness, such as trachoma and river blindness, must encourage investments in initiatives in favour of ocular health.The appeal that is launched is that of carrying on with the pathway of investment in the prevention of blindness and rehabilitation of sight, initiatives that allow us, given present knowledge, to help millions of our brothers and sisters.

Stimare il numero di persone nel mondo e la loro distribuzione

nei vari paesi e regioni è un lavo-ro essenziale per poter identificare dove gli interventi siano necessari.

Tale compito è svolto sin dagli anni ’90 dall’Organizzazione mon-diale della Sanità, che ha pubbli-cato regolarmente delle stime di quante persone nel mondo soffra-no di cecità, o siano ipovedenti, e per quali cause principali nelle va-rie fasce di età.

I dati più recenti, pubblicati nel 2010, stimano in 285 milioni il nu-mero di persone con un deficit visi-vo grave nel mondo: di queste, 246 milioni sono ipovedenti e 39 milio-ni sono cieche1.

Dall’esame delle cause di tale deficit, si può evincere che, in oltre l’80% dei casi, questo deficit è cu-rabile o prevenibile. Questo legitti-ma il considerare la cecità evitabi-le un problema di salute pubblica a livello mondiale.

Le fasce di età non sono tutte interessate nello stesso modo: cir-ca l’80% del deficit visivo si trova tra le persone nella fascia di età oltre i 50 anni; il numero di per-sone in questa fascia di età è cre-sciuto del 18% negli ultimi 6 an-ni, in tutti i paesi del mondo. Di conseguenza ci si attendeva di ri-levare un proporzionale aumento del numero di persone con un de-ficit visivo grave, e invece, rispet-to alle stime del 2004, il numero di ipovedenti e ciechi nel mondo è diminuito del 9%.

Questa è un’ottima notizia: vuol dire, in larga parte, che gli investi-menti dei governi, delle organizza-zioni di aiuto allo sviluppo, delle organizzazioni non governative a sostegno di interventi mirati prin-cipalmente alla prevenzione del-la cecità o all’aiuto allo sviluppo sanitario o sociale hanno avuto un impatto misurabile su larga sca-la. La riduzione è particolarmen-te sensibile nella regione africana, dove i progressi nello sviluppo dei sistemi sanitari e sociali sono par-ticolarmente evidenti.

Resta il fatto che una popola-zione numerosa quanto un virtuale 4° paese per popolazione al mon-do soffre quotidianamente a cau-sa di un handicap che potrebbe, nell’80% dei casi, essere curato o evitato.

Un bambino ogni 5 minuti di-venta cieco, ed il 50% dei casi po-trebbe essere evitato o curato; i bambini necessitano di specialisti esperti nella gestione delle loro pa-tologie oculari, ma l’investimento nella prevenzione e cura della ceci-tà infantile è un imperativo morale indiscutibile.

La prima causa di ipovisione nel mondo sono i vizi di refrazione non corretti (miopia, ipermetropia

31DOLENTIUM HOMINUM N. 80-2012

ed astigmatismo), che sono nella maggioranza dei casi correggibili con una spesa estremamente mo-desta, ed affliggono soprattutto i bambini, che vedono ridotta la pro-pria capacità di profittare dell’edu-cazione scolastica per uscire dal circolo vizioso dell’ignoranza, che si traduce in povertà e malattia.

La prima causa di cecità è la ca-taratta non operata, prevalente ol-tre i 50 anni: un intervento di pochi minuti, dal costo di circa 30 euro, potrebbe ridare la vista ad oltre 20 milioni di persone attualmente cie-che.

La lotta alla cecità evitabile, all’handicap visivo grave non pas-sa solo attraverso la prevenzione e la cura, ma anche attraverso la di-sponibilità e l’accesso ai servizi di riabilitazione, per permettere a chi ha perso la vista, del tutto o in par-te, di non vedersi negato il diritto ad una vita piena e pienamente vis-suta. Ciò vuol dire la possibilità di accedere all’educazione, al lavo-ro, ad una realizzazione dell’essere umano come pienamente integrato nella società di appartenenza, sen-za barriere o stigma.

Molto è stato fatto e si fa nell’ul-timo decennio per sensibilizzare i

governanti ed i responsabili delle politiche socio-sanitarie sulle pos-sibilità offerte dalla prevenzione della cecità e la riabilitazione vi-siva offrono agli investimenti, ed ai ritorni importanti, economici e morali, che tali interventi garan-tiscono; i dati in nostro possesso supportano tale affermazione, e l’evidenza scientifica ci permet-te di dire che l’intervento a favo-re della prevenzione della cecità e della riabilitazione visiva sono tra i più redditizi che si offrano all’in-vestimento sanitario nazionale ed internazionale.

In un mondo che invecchia, do-ve le malattie croniche aumentano oltre a quelle infettive, il fatto che un numero crescente di paesi ab-biano con successo eliminato pato-logie causa di cecità come il traco-ma (causato dalla povertà estrema ed alla mancanza di acqua e di igiene), l’oncocercosi (la cecità dei fiumi, trasmessa da una mosca che si riproduce nei fiumi di alcuni paesi d’Africa), deve incoraggiare l’investimento in salute oculare. Le campagne per il controllo di difetti visivi nei bambini, particolarmente adeguate nelle scuole, l’educazio-ne sanitaria di base, per stimolare

l’attenzione ed educare genitori ed insegnanti all’importanza della correzione tempestiva dei difetti di refrazione, sono interventi dal fa-vorevole rapporto costo-benefici.

L’aumento delle patologie lega-te all’età (degenerazione macula-re senile), alle malattie sistemiche in aumento (retinopatia diabetica), alle cause croniche che vanno cu-rate nel corso della vita (glauco-ma) deve stimolare ad investire nello sviluppo dei sistemi sanita-ri oftalmici, nella prevenzione pri-maria e secondaria, nella diagnosi precoce.

La prevenzione della cecità e la riabilitazione visiva sono interven-ti che permettono oggi, con le co-noscenze attuali, di aiutare i nostri simili a beneficiare di un miracolo che dovrebbe essere accessibile a tutti, ma per milioni di nostri fra-telli non lo è.

Nota

1 Secondo la classificazione internaziona-le delle malattie (ICD-10) un deficit visivo grave è una capacità visiva inferiore a 3/10, definita come: ipovisione se inferiore a 3/10 ma superiore o uguale a 1/20, cecità è una acuità visiva inferiore a 1/20.

II.2 Increasing Access to Eye Care and Rehabilitation in Developing Countries

DR. WING-KUN TAMPresident of Lions Clubs International,China

It is an honor for me to be here today. I want to thank the Holy

Father, the Pontifical Council for Health Care Workers and CBM for convening this study group. This is a great opportunity for people of goodwill to come together to bring sight to the blind and improve the lives of those with vision impair-ments. I am honored to be among the groups and organizations here who are dedicated to helping oth-

ers and fighting these challenges together.

What I will talk about today chiefly is the role volunteers can play in reducing blindness and vi-sion impairment. Lions are volun-teers with the motto “We Serve,” and are well known for our in-volvement with vision. I am the international president of Lions Clubs International. In my day job, I run an international cargo com-pany. But what you may not know about me, is that I am just another Lion volunteer, like the other 1.35 million Lions around the world, and I know there are a number of other Lions in the room. So I want

to talk about the role volunteers play in combating vision impair-ment and increasing access to eye care and rehabilitation.

Unfortunately, blindness and vi-sion impairment often is an over-looked challenge. That is very regrettable especially since a ma-jority of vision impairment is a challenge that can be overcome or significantly improved with the right resources. We have the tech-nology. We have the know-how. The challenge is to provide access to eye care.

As we know, 9 of 10 people who are blind or with vision impairment live in developing nations. So it is


III. THE PRINCIPAL CAUSES OF AVOIDABLE BLINDNESS AND STRATEGIES FOR PREVENTION AND CURE

III.1 Cataract – the Leading Cause of Blindness

DR. ABDULAZIZ ALRAJHIPresident of the Middle East African Council of Ophthalmology (MEACO),Saudi Arabia

DR. M MANSUR RABIUThe Prevention of Blindness Union, Riyadh, Saudi Arabia

What is Cataract?

Cataract is the opacification of the crystalline lens of the eye. It is usually a gradual painless process that takes place over years. And it occurs mainly with increasing age. As such, it is predominantly to be found in elderly people.

However lens opacification may occur due to some ailments/conditions at young or adult age. These are called secondary cata-ract. Cataract that occurs at birth is called congenital cataract. But most cataract is due to old age, to so-called age related cataract. And this talk will concentrate on this.

The Burden of Cataract

Cataract blindness

In 2010 WHO estimated the to-tal number of blind people in the world at 39.36 million. These are people with vision that is worse than 3/60 (20.400) in their bet-ter eye. Of these, cataract is the major cause, being responsible for 51% of blindness. This means

that there about 20 million people who are blind because of this con-dition worldwide. There are an-other 74 million with some vision loss due to cataract as well.1

The number of people who are blind due to cataract varies in dif-ferent parts and regions of the world as cataract is responsible for over 60% of blindness in some parts of the world.

The incidence of cataract blind-ness globally is not well known. In 2000 Allen Foster reported a rough estimate of 5 million cata-ract blind yearly.

Cataract Visual Impairment – Operable Cataract

Cataract blindness is the end spectrum of a gradual progressive vision impairing condition. Cata-ract often becomes noticeable to a person when it begins to impair his/her vision. At the stage when this visual impairment affects a person normal life and the con-sulting doctor feel it needs to be operated it is termed ‘operable

cataract’. This often is much ear-lier than the stage when cataract causes the degree of vision im-pairment called blindness. Thus the number of people with oper-able cataract is much higher than the number of people with cata-ract blindness. The level of lens opacity (cataract) that is deemed ‘operable’ varies according to the visual demand of the person, the surgical skills of the doctor, the facilities available, and access to services in the environment .

Many reports, especially in de-veloping countries, often use lens

opacity that results in vision of less than 6/60 in the eye as ‘oper-able cataract’. There is no global data on the number of people or eyes with lens opacity worse than 6/60.

Looking at available data from Africa, Lewellen,2 using com-puter modeling and results of RAAB surveys across West and East Africa, recently reported that the prevalence and incidence of cataract opacity amongst fifty-

Sources: Global burden of Disease data: WHO website; Serge et al.: Bull WHO 2004


year-olds and older varies wide-ly even within Africa. The inci-dence of cataract responsible for r vision less than 6/60 in one or both eyes per year varies from 1.1% in Rwanda to 3.4% in Ma-li. Using the least prevalence and incident values to extrapolate the number of persons with uni- or bi-lateral lens opacity of vision 6/60, it was suggested that there were over 5 million people with ‘oper-able cataract’ in one or both eyes. Furthermore annually there will be another 800,000 more people developing this condition. This is going to increase astronomically due to increase life expectancy and the likely increase in demand for surgery at a much earlier level of visual loss.

So in Africa alone a very con-servative estimate suggests that there needs to be about 800,000 cataract surgeries each year only to take care of incidence, with-out even tackling the backlog of over 5 million people who already have the problem.

Currently the estimated num-ber of cataract surgeries per year in Africa is not exactly known. However the WHO Afro report stated the average CSR in Africa is 467, meaning that the average number of cataract surgeries per year in Africa is about 380,000. This is not even half of the pro-jected incidence.

The Future

The incidence will surely in-crease as life expectancy is in-creasing across the world in-cluding Africa. Furthermore, as cataract services improve and the literacy and economic status of people improves there will be in-creased demand for surgery even at less visual acuity than 6/60, and this means that the number of in-dividual operable cataract may triple further if people seek an op-eration at vision say of 6/24.

Aetiogenesis

Many factors have been impli-cated as risk factors in catarac-togenesis: they include old age, UV rays, smoking, steroids, lean body mass, a dehydration crisis, even cooking. The wide range of

risk factors only suggests that we do not really know the risk fac-tors, especially in old age. One other explanation gaining ground currently is the ‘free radical the-ory’, i.e. cellular damage from reactive oxygen species. Envi-ronmental sources of this species included solar radiation, biomass fuels and tobacco smoking. How-ever, antioxidants like vitamins C and E, and the carotenoids lutein and zinc, have not shown con-sistent benefit in epidemiological studies..3,4

Treatment

For now cataract is treated on-ly by surgery. The procedure in-volves removing the opaque lens and replacing it with an artificial lens that will provide the refrac-tive function of the natural lens removed. Though different tech-niques are used the most common and most effective procedure is the phacoemulsification proce-dure. With improved technology and surgical skills the surgery has not only become very successful in restoring vision but also very fast and simpler.

Why Invest in Cataract Services?

The burden that the blind per-son is to himself, his family and his community has long been rec-ognized. In economic terms, vari-ous studies have demonstrated this amply.

The cost effectiveness of interventions

Cost per DALY saved has been put at $20-40 dollars. This makes cataract surgery and other eye in-terventions among the most cost effective health interventions. DALY is a time-based measure that combines years of life lost due to premature mortality and years of life lost due to time lived in states of less than full health.5

Interventions for visual disor-ders are as cost effective as HIV/AIDS interventions, as depicted below

Economic Returns

a. An economic study in Paki-stan reported that rehabilitating cataract blind people has an eco-nomic benefit worth $2.5 billion over a 10-year period. This repre-sented about 3.83% of the coun-try’s GDP at that time. The per annum productivity gains from rehabilitating all blind people in Pakistan (mostly cataract) rep-resents 0.8% of GDP, which is higher than the total annual pub-lic spending on health.6

b. A study on the economic benefit of cataract surgery in three countries (Kenya/Bangladesh/Philippines) showed that cataract surgery can alleviate poverty, es-pecially among the most vulner-able. The research showed that after cataract surgery the aver-age household economic gain in the three countries was US $7 per

Sources: Lopez AD et al., ‘Global and regional burden of disease and risk factors, 2001: systematic analysis of population health data’, The Lancet, 2006, 367:1747–1757; and comment by Chiang PPC et al., ‘Visual impairment and global burden of disease’, The Lancet, 2006, 368: 365.


capita per month. With an average family size of five, that means US $35 a month or US $420 a year. The average monthly family in-come in Bangladesh is approxi-mately US $126. Thus households with persons with cataract had 20-28% lower per capita household expenditure than household with people with normal vision. Af-ter surgery, per capita household expenditure was similar to con-trols (those who had not under-gone cataract surgery). Cataract surgery increased the number of people involved in productive ac-tivities by up to 50%, thus helping to relieve poverty.

In terms of daily activities and time-use the study showed that cataract surgery increased the number of people involved in pro-ductive activities by up to 50%, thus helping to relieve poverty.

As regards quality of life before surgery, cataract patients were four times more likely than people with normal vision to report problems with self-care, mobility, usual ac-tivities, pain/discomfort and anxie-ty/depression. After surgery, qual-ity of life improved substantially.

Interventions

So where are we now?

Since the start of “VISION 2020: The Right to Sight”, the

number of cataract surgeries car-ried out has increased. However, there is still a wide gap between the burden of the pathology and the surgeries being done.

The number of cataract blind people (which is much less than the number of people needing cataract surgery) compared to the number of surgeries done, shows a wide gap in regions like Africa, WPR and SEA. This is demon-strated in the table below:

The ‘Impasse’

The conventional provision of cataract surgeries at hospitals at the current rate will not be able to address this burden of cataract

visual impairment, especially in areas where the burden is highest. Over the years various approach-es have been developed, especial-ly by NGDOs, to provide mass surgeries for cataract cases in ar-eas of the world with the highest burden, like Africa, Asia and Lat-in America.

Some of the major approach-es provide the services to a larg-er number of people in a shorter time period and in a less expen-

sive way. A major issue to each approach is its sustainability for a condition that cannot be elimi-nated.

Daniel Etya’ale has categorized these approaches as:

Cataract blind persons compared to the number of surgeries per year for WHO regions. *No full data for the Euro zone.

Outreach Type Main objectives and strategies Potential for sustainabilityA. Surgical eye camp

– Screen and offer surgery on site to as many people as possible

– Low in general, except where long-term local support and commitment can be guaranteed

B. Screening eye camp

– Screen, refer/transport candidates for cataract surgery to base unit

– Low, for the same reasons as (A) aboveCould be justified as a means to build up or strengthen existing eye centers,

C. Mobile eye clinic

– A toned-down variant of (B), often organized and run as an equivalent of an Outpatient Department (OPD) of the base eye unit

– Same as (B) above

D. Using/working with community-based rehabilitation (CBR) or other community-based programs

– Use an existing CBR programme to deliver primary eye care, detect, assess and refer or transport – use community-based and -approved workers, e.g. cataract finders or other health workers

– Uncertain when the community is a passive beneficiary of these services and/or when most of the running cost is borne by donors or sponsors– Good to excellent, when true ownership by the community is actively sought and achieved, or some sort of cost-sharing is introduced from the outset

E. Creating eye (vision) centers strategically located in needy areas

– Here priority is given to the setting up of permanent primary and secondary eye units, with the view to improve geographic coverage and access to eye care

Good to excellent, especially: – When planned and implemented in close partnership with the community; – When combined with other strategies that proactively seek out the needy and ‘hard-to-reach’ patients


Current Major Challenges to Cataract Services in Most Developing Countries

Non prioritization of eye care and cataract services by govern-ments.

Alienation of eye care and cataract services from health structures and programs mainly through vertical programs.

Sustainability concerns regard-ing ‘mass surgery’ programs.

Inadequate efficiency in some programs.

Inadequate resources, e.g. a shortage of human resources.

Less than optimal coverage of services.

Inequity in service provision, e.g. gender imbalance.

Quality concerns in services – less than optimal visual, psycho-logical and quality of life out-comes.

Scaling Up Cataract Services –More Efficient Delivery Service

To cope with increasing burden of cataract vision loss both the traditional hospital based services and the outreach services need to improve in efficiency, quality, in-novations and sustainability.

Improving outreach programs:7

Careful planning of the pro-gram.

Community involvement and ownership.

Government involvement and leadership.

A good monitoring and evalua-tion system.

A structure and clear mecha-nisms for dialogue, problem-solv-ing and co-ordination among all stakeholders.

Improving hospital services:8

Systems must optimize the bal-ance between resources and pa-tient load. The success of the Ara-vind eye hospital in India in mass surgeries has been attributed to systems in place which include: standardization; division of labor; balancing resources; and micro-level planning.

Measures to Scale Up Cataract Services

Improving efficiency and or-ganization of cataract and eye care services within existing health systems with all stakehold-ers, including the private sector, for sustainability.

All NGO services involved in cataract services should engage with, and support, the existing health system through capacity and institutional building to en-sure sustainability, affordability and accessibility.

Increasing investment in cata-ract and eye care through train-ing of eye care workers and their retention to increase quantity and quality of workers in needy re-gions and the provision of facili-ties.

Cataract services and eye care services should be built with ac-tive community participation for cost-effectiveness, ownership and sustainability.

Cataract services should incor-

porate effective monitoring and quality assessment measures.

The development of more effi-cient and sustainable eye care sys-tems that provide high quality and equitable services.

For remote areas, appropriate targeted outreach services that en-sure sustainability should be set up.

References

1 PaScolInI d., MarIottI S.P.M., ‘Global estimates of visual impairment: 2010’, Brit-ish Journal Ophthalmology Online First published December 1, 2011 as 10.1136/bjophthalmol-2011-300539.

2 leWallen S., WIllIaMS t.d., dray a., Stock B.c., MathenGe W., oye J., nkurI-kIye J., kIManI k., Müller a., Courtright P., ‘Estimating incidence of vision-reducing cataract in Africa: a new model with impli-cations for program targets’, Arch. Ophthal-mol. 2010 Dec;128(12):1584-9.

3 Fletcher a.e., ‘Free radicals, antioxi-dants and eye diseases: evidence from epi-demiological studies on cataract and age-related macular degeneration’, Ophthalmic Res. 2010;44(3):191-8. Epub 2010 Sep 9.

4 BonneFoy M., draI J., koStka t., ‘An-tioxidants to slow aging, facts and perspec-tives’, Presse Med. 2002 Jul 27;31(25):1174-84.

5 Vision 2020 The Right to Sight. Glob-al Initiative for the elimination of avoid-able blindness. Action plan 2006-11: page 7. World health Organization. Geneva 2007.

6 MalIk S.M. et al., ‘Productivity Gains in rehabilitating the blind in Pakistan’, Sightsavers International 2010.

7 kuPer h., Polack S., MathenGe W., euSeBIo c., Wadud z. et al. (2010) ‘Does Cataract Surgery Alleviate Poverty? Evi-dence from a Multi-Centre Intervention Study Conducted in Kenya, the Philippines and Bangladesh’, PLoS ONE 5(11).

8 etya’ale d., ‘Beyond the clinic: ap-proaches to outreach’, Community Eye Health J. 2006;19(58): 19-21. OUTREACH APPROACHES. J. Comm. Eye Health 2000;13(34): 22-23.

9 thulaSIraJ r.d., SaraVanan S., ‘Pro-ductivity: getting cataract patients ‘through and out’’ J. Comm. Eye Health 2000;13(34): 22-23.


III.2 Onchocerciasis and Trachoma

DR. ALLEN FOSTER Director of the Christian Blind Mission (CBM) Germany.Director of the International Center for Eye Health (ICEH) Great Britain

Trends in Global Blindness

Between 1975 and 1995 it is es-timated that the number of blind people in the world increased from 28 to 45 million. At this time the infective eye diseases – trachoma and onchocerciasis (al-so called river blindness) – were major causes of blindness.

This article describes these two diseases and how recent advanc-es in treatment are reducing the prevalence of disease and visual loss from these diseases.

Onchocerciasis

Onchocerciasis is a parasitic in-fection with a filarial worm called Onchocerca volvulus. The para-site is transmitted to man through the bite of a black fly called Sim-ulium. The adult worm lives for many years in the person, often without symptoms, but produces offspring (babies) called Microfi-laria. The microscopic microfilar-ia cause inflammation in the skin and in the eyes. The symptoms may take years to appear and in-clude itching, redness of the eyes and gradual reduction in vision.

Onchocerciasis affects millions of people in approximately 30 countries of Africa and 6 coun-tries of the Americas. Control of

the disease was undertaken by re-ducing the breeding sites of the simulium fly so that transmission of the disease by the flies from person to person was reduced. This vector control in West Africa has been successful, but it is ex-pensive and takes many years to reduce the prevalence of infection in people.

In the 1980s a drug was found which if taken once per year kills the microfilaria and reduces the symptoms of disease. The phar-maceutical company has made the drug, Ivermectin, trade name Mectizan, freely available for people with, or at risk of, oncho-cerciasis. The drug is given to people once a year in mass com-munity distribution programmes, which are planned and directed by the communities themselves. Currently over 70 million people are receiving treatment annually.

Trachoma

Trachoma is a bacterial eye in-fection with the organism Chla-mydia Trachomatis. The bacte-ria are transmitted from child to child by flies which are attracted to children’s eyes by facial and eye discharges. The repeated in-fection can carry on for months or even years, often with few symp-toms. Over the course of years the inflammation produces scarring of the inside of the upper eyelid resulting in turning in of the eye-lashes (trichiasis) which causes pain and gradual loss of vision from scarring of the cornea.

Trachoma affects millions of people in approximately 50 countries of Africa, Asia and the

Americas. Control of the disease consist of the “SAFE” strategy which stands for “S” – surgery to turn out in turning eyelashes; “A” – mass drug administration of the antibiotic azithromycin, once per year to communities with high levels of disease (TF 10+%); “F” – promotion of facial cleanliness particularly in children to clean facial discharges away; “E” – im-provement in environment, better water and sanitation.

Pfizer through the Internation-al Trachoma Initiative have made azithromycin available as a dona-tion for the treatment of endemic trachoma communities. Currently approximately 50 million people are being treated each year.

Lessons learnt

– Drug donation programmes have played a major part in reduc-ing infection and blindness from onchocerciasis and trachoma

– Effective distribution sys-tems at the community level are required for the drug donations, with non-governmental agencies playing an important role in ca-pacity building, implementation and coordination

– The affected communities play an essential role in deter-mining how best to distribute the medicines/interventions

– Political commitment by na-tional governments, donor agen-cies and pharmaceutical compa-nies is essential to scale up these programmes both nationally and regionally

– Partnerships at international, national, district and community levels are critically important.


III.3 Blindness Due to Retinal Diseases, Specifically Diabetic Retinopathy and Age-related Macular Degeneration

PROF. DONALD J. D’AMICO, MDProfessor and Chairman,The Betty Neuwirth Lee and Chilly Professor,Weill Cornell Medical College;Ophthalmologist-in-Chief,New York-Presbyterian HospitalNew York, New York, USA

The gift of vision begins with a healthy eye that is capable

of capturing light, focusing an image, transmitting it clearly to the retina, and converting it to an electrical signal that, on passage out of the eye by way of the optic nerve, creates an image our brain can perceive. In the center of the eye we see the vitreous, which is a large clear gel which maintains the shape of the eye, and further back, we see the retina, which lines the inside surface of the eye like wall paper. The retina is often compared to the film in a camera, and it is in the retina that the ener-gy of the light is transformed into an electrical signal that is carried out of the eye by the optic nerve to the brain. So that we can be ori-ented, it is important to know that we can look into the eye and see the retina directly, and here is a normal retina shown with a spe-cial panoramic camera. The very center of the retina is known as the macula and is the area with our best visual acuity, with the re-mainder of the retina providing our peripheral or side vision. For comparison, you can see an eye with a large upper retinal detach-ment in the in this slide.

The retina is one of the most elegant and complicated tissues in the human body. If we take a magnified look, we see that it is composed of multi-layered nerv-ous tissue. In our eyes, after hav-ing passed through the front of the eye and the vitreous gel, light

actually passes across the clear retina to reach one of the mil-lions of photoreceptors, i.e. rods and cones, and it is here that the light to electric conversion takes place. These delicate photorecep-tors are nourished and supported by a dedicated underlying lay-er of cells called the retinal pig-ment epithelium or RPE, and this partnership is critical to the health and function of each cell. A sepa-ration of the retina from the RPE is known as a retinal detachment, and as you might imagine, breaks the contact between these two layers and rapidly produces visu-al loss. The retina, although main-ly clear, has blood vessels near its inner surface facing the vitreous gel, but the photoreceptors and RPE obtain their blood flow and nutrition from the choroid, a vas-cular layer underneath the RPE and just inside the leathery sclera of the eye.

Diseases of the retina are ex-tremely important causes of vis-ual loss worldwide. Because it is nervous tissue like the brain, the retina cannot be replaced or trans-planted by our current treatments. There are some early and prom-ising clinical trials using elec-tronic chip implants, but the great majority of our work with retinal diseases consists of trying to pre-serve or restore the function of this very fragile and irreplaceable tissue by treatment with drugs, la-ser, and surgery.

Although there are many reti-nal disease that are extremely im-portant in a global perspective, I will limit my remarks to diabetic retinopathy and macular degen-eration that are both in the WHO top ten list of Priority Eye Diseas-es. Diabetes and its complications is an enormous burden on world populations, and unfortunately it is increasing. The WHO has esti-mated that there were 171 million

people worldwide with diabetes mellitus in 2000 and predicted that 366 million people will have diabetes by 2030. One of the most severe consequences of diabetes is the development of retinopa-thy, which is the most common cause of retinal blindness during the middle years of life, that is, during the most productive years of life. WHO has also estimated that in 2002 diabetic retinopathy was responsible for 5% of world’s blind, totaling approximately 5 million individuals. Indeed for much of the world’s population, it will be the ability to prevent di-abetes-related visual impairment that will determine if we are suc-cessful in fighting an epidemic of retinal blindness.

Diabetes produces profound changes in the blood vessels in the retina. At first, the vessels in-volved may not be in the central macula, and therefore the patient may develop retinopathy while being unaware of the problem. As the disease progresses, it caus-es an incompetence or leakage in the inner retinal blood vessels and this is manifest as a swell-ing of the retina known as macu-lar edema. You seen an example in which the macula has accumu-lated yellow deposits of fat, and such a patient would undoubtedly be legally blind. Here you see a much earlier phase of the disease in which the blood vessels are damaged and are leaking fluid and red blood cells into the retina, in-dicated by the outward diffusion of bright dye during a diagnostic test in which fluorescein dye is given intravenously and then the retinal vascular leakage is detect-ed with a special camera. This is known as non-proliferative retin-opathy, and usually causes vis-ual loss by a visually-damaging accumulation of fluid known as macular edema. A patient such as


this would have a moderate to se-vere reduction in their central vi-sion, but would probably be able to continue basic daily tasks if the other areas of the retina, and their peripheral vision, remain relative-ly normal.

As diabetic retinopathy pro-gresses, many retinal vessels be-come blocked, and this loss of blood flow damages the function of the affected area of the retina. These areas deprived of blood flow are called ischemic areas, and they can be demonstrated on fluorescein testing as dark patch-es against the light grey of areas that have continued normal circu-lation. Still further in the process, these dying areas of retina send biological signals to the remain-ing retina and a process of new blood vessels or neovasculariza-tion develops known as prolifer-ative diabetic retinopathy. While one might be tempted to think that these new blood vessels might of-fer some restoration or benefit, they are highly abnormal; unless they are promptly treated, they will cause certain blindness for the eye due to bleeding into the vitreous, overgrowth of the reti-na with fibrovascular scar tissue, or the development of a traction retinal detachment in which the new blood vessels literally pull the retina from its needed contact with the underlying RPE. Shortly after they appear, these new ves-sels can be eliminated with a la-ser treatment known as panretinal photocoagulation, but if they pro-gress to bleeding and retinal de-tachment, vision can only be re-stored by the most difficult and complicated vitreoretinal surgery.

What can be done to prevent diabetic blindness in the popu-lations of the world? There are many possibilities and also many difficulties, and I will try to place these in an understandable con-text. We have mentioned that the incidence of diabetes itself is in-creasing worldwide, but in devel-oped countries, the percentage of diabetic patients developing any form of retinopathy is actually decreasing compared to the past. This is related to improved med-ical management of diabetes in these countries, including better control of diet, weight, and hyper-

tension, etc. through education, drugs, exercise, and dietary modi-fications. This is a welcome posi-tive trend, but we must note that no such helpful positive trend is occurring in the developing world in which the percentage of diabet-ic blind is increasing directly in line with the increase in diabetes. Second, while careful medical management alone cannot reverse the damage of retinopathy, it has been clearly established that care-ful control of blood sugar delays or even prevents the development or progression of retinopathy. So our first and most important tasks are to improve the overall health of our populations and to provide for physician and patient educa-tion, dietary modifications, drugs, and other tools so that control of blood sugar levels is improved. These are bedrock efforts, but in a world where 14% of the world’s population is undernourished and 11% lacks clean drinking water, the challenges are enormous.

Our second task relates to de-tection of diabetes mellitus and therefore diabetic retinopathy. Even in a country as rich as the United States, 5.2 million diabet-ics are unaware that they have the disease, so we must imagine that the number of undetected patients in the world with diabetic retin-opathy is truly staggering. Again, in the developed world, diabetics benefit from a yearly eye exam-ination, but in developing coun-tries, this will be difficult given that examiners are in short sup-ply. Beyond the basic problem of diabetes mellitus detection itself, the best hope for improving dia-betic retinopathy detection is two fold: education of more skilled examiners, and continued im-provements in telemedicine in which the evaluation of diabet-ic retinopathy can be separated from the acquisition of diagnos-tic retinal photographs. If retinal photography techniques can be simplified and disseminated, such a strategy could reduce the level of medical expertise needed in re-mote locations.

If we could detect diabetics, and detect diabetics with visual-ly-significant retinopathy, what would be our most effective ac-tions? Again, the difference is

striking depending on the socio-economics of a given country. In the United States, for example, the main problem is how to treat mild to moderate forms of mac-ular edema, and this can usually be accomplished with intraocu-lar injections of anti-VEGF drugs and with laser therapy. Converse-ly, in the developing world, un-treated diabetic retinopathy most frequently presents as either ex-tremely severe macular edema (count fingers vision or worse) or advanced and longstanding trac-tion retinal detachments which leave the eye totally blind. A number of years ago I was dem-onstrating a new surgical tech-nique in Mexico, and I planned to operate on four or five patients with severe traction retinal de-tachment due to diabetes. As I viewed a large crowd in the open-air waiting area of the hospital, I was amazed to learn that over one hundred patients had come hoping to be chosen for my treat-ment, and furthermore, that the great majority had an advanced diabetic traction detachment in both eyes!

So, our treatment options will depend on the varied socioeco-nomic situation of each country, i.e. for more developed coun-tries, we may have the chance to treat moderate visual loss due to macular edema with anti-VEGF drugs and laser, and perhaps even to train some surgeons to remove vitreous hemorrhage and repair a traction retinal detachment. Less developed countries will strug-gle with retinopathy detection, and its patients will unfortunate-ly present with blindness due to advanced proliferative diabetic retinopathy. It is probably imprac-tical to train the legion of skilled surgeons needed to treat such an advanced and complex condi-tion, but if we were able to train individuals to perform prophylac-tic panretinal laser photocoagu-lation on these patients, it would be an important advance. We re-cently trained a retina specialist to practice in Mauritius Island in the Indian Ocean, and within his first few weeks, he had performed hundreds of such laser treatments, saving these patients from certain blindness.


So, to summarize, for more de-veloped countries, we need to fo-cus our efforts on diabetes con-trol, diet, and overall health, with additional efforts at retinopathy detection and treatment including better drug treatments and train-ing surgeons to perform relatively advanced eye surgery. For less de-veloped nations, we will struggle with the basics of diabetes treat-ment and retinopathy detection, but our greatest help will be in laser treatment for proliferative retinopathy, and anything more advanced, such as intraocular drug therapy or surgery for trac-tion retinal detachment, will un-fortunately remain an exotic lux-ury at present.

Age-related macular degenera-tion presents completely differ-ent challenges and demographics compared to diabetic retinopathy. The WHO ranks it as the third most important cause of global blindness after cataract and glau-coma. Whereas diabetic retinopa-thy strikes middle-aged Hispanic and black populations with high frequency, age-related macular degeneration strikes patients in older age in predominantly Cau-casian populations. Consequent-ly, affected patients tend to live in countries that have more resourc-es to detect the disease and pro-vide therapy. The incidence is re-duced in less developed countries due to a host of factors including shortened lifespan, racial and ge-netic predisposition, dietary hab-its, and many other influences that are difficult to quantify.

Age-related macular degenera-tion consists of two forms, name-ly the dry form or the wet (or ne-ovascular) form. The dry form typically presents as the accumu-lation of deposits in the macula known as drusen or as an atrophic loss of tissue in the central macu-la known as geographic atrophy. The dry form may remain mild or may itself cause moderate cen-tral visual loss due to damage to the central retina, or in a small percentage of cases, it may pro-gress to the wet form in which blood vessels from the choroid invade the spaces under the RPE and retina and typically cause an acute drop in visual acuity. These

abnormally located vessels do se-vere damage to the central retina by distorting the overlying mac-ula, by leakage that may be fluid or blood, or most severely, by cre-ating a macular scar. In the past few years, intraocular injections of anti-VEGF agents have shown a remarkable ability to reverse the process and restore vision if ad-ministered early in the disease, but the treatment is complicated and costly, requiring sophisticat-ed monitoring and frequent in-traocular injections.

We may therefore view age-re-lated macular degeneration as a pyramid, with the base being ful-ly normal individuals, the middle section being those with the dry form and variable vision loss, and the very apex of the pyramid being those with wet macular degenera-tion. Paradoxically, we have ex-citing new drug treatments for the very few at the top with wet mac-ular degeneration, but treatment of these patients will be practi-cal or possible for only relatively well developed nations for the im-mediate future. Somewhat more promising are studies that have explored the factors that might influence progression from dry to wet. Smoking has been proven to be an extremely damaging risk factor for disease progression. Other studies are suggesting, but have not yet completely proved, that another risk factor for pro-gression is the lack of a healthy diet including antioxidants, min-erals, and other components such as lutein and omega 3 fatty acids. Regarding the bottom part of our pyramid and our wish to keep pa-tients from developing any evi-dence of dry macular degenera-tion at all, unfortunately, as yet we have no preventive therapy despite an enormous amount of research and the discovery of ge-netic and other clues.

So, for age-related macular de-generation, we see that the most effective efforts would be preven-tative and would include programs to reduce smoking and perhaps to provide targeted dietary supple-mentation. As regards treatment of advanced ARMD, intraocular injection of less expensive medi-cations such as bevacizumab may

become within reach for more rapidly developing countries, but more widespread treatments must await cheaper, longer acting, and more easily administered forms of therapy. More readily available—and frequently overlooked—are simple high-plus glasses or mag-nifying low vision aids to allow improved near vision even for a patient with macular scarring. As part of a United Nations mis-sion, I recently spent time in the Mbola Villages cluster in Tanza-nia distributing reading glasses in a remote village, and I quickly learned how greatly a simple high plus pair of reading glasses was appreciated by patients with mac-ular damage from many causes, allowing them to cook and per-form other simple near tasks that were impossible without magnifi-cation.

In closing, it is clear that there are many challenges ahead in our efforts to address the suffering caused by diabetic retinopathy, age-related macular degenera-tion, and other form of retina-re-lated blindness. There have also been remarkable advances in dis-ease prevention, detection, and treatment, ranging from the sim-ple, such as eyeglasses, to the complex, such as advanced vit-reoretinal surgery. Our greatest challenge, and greatest hope, is to identify the appropriate strate-gy for a given situation, and then work cooperatively and diligently to reduce retina-related blindness with the many effective preven-tions and interventions that are available; with effort, these tools are certain to increase in number and grow more effective in the future. Thank you again for the great honor to participate in this most important congress.

References

Priority Eye Diseases, WHO publica-tions.

Prevention of Blindness from Diabetes Mellitus. Report of a WHO consultation in Geneva, Switzerland. 9-11 November 2005. Published WHO 2006.

A randomized, placebo-controlled, clini-cal trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vi-sion loss: AREDS report no. 8. Arch Oph-thalmol. 2001;119:1417-36.


III.4 Childhood Blindness

DR. ANDREA MOLINARIMedical Doctor in Pediatric Ophthalmology,Metropolitan Hospital of Quito, Ecuador

Sight is the sense that gathers the most information about our

environment and the only sense responsible for organizing other forms of sensory input. Consid-ering that 80% of the informa-tion obtained during the first year of life is through sight, childhood blindness is a tragedy that will af-fect not only the child but also his or her family.

Childhood blindness can be prevented or treated in 40% of cases overall. However, in devel-oping countries, 75% of child-hood blindness is preventable.

Only 3% of the world´s blind populations are children. How-ever, because children have a life-time of blindness ahead of them, the number of “blind person years” resulting from blindness starting in childhood is second only to cataract. It is calculated that childhood blindness repre-sents 75 million “blind years”. Fifty percent of children who be-come blind before the age of two years die before the age of five. This, therefore, reduces the ob-served prevalence of childhood-related blindness.

Childhood blindness is 10 times more frequent in the world´s poorest countries. This frequency is calculated at 0.1/1000 children aged 0-15 years in the wealthiest countries and at 1.1/1000 children in the poorest ones. Out of the 1.5 million total of blind children in the world, one million live in Asia and Africa.

Children with eye problems of-ten require detection through the vision screening process. This generally occurs because a child that has been born with a visual problem is not aware of his or her disability and is unable to articu-late to others that he or she has a visual problem. In countries

where this screening does not take place on a regular basis, precious time is lost, and when the prob-lem is eventually discovered it is often too late for adequate treat-ment of the illness.

A constant feature of pediatric eye illness is that the patient needs an advocate. The pediatric pa-tient requires a special approach as does the family. Pediatric oph-thalmologists or pediatric orient-ed ophthalmologists are better prepared to manage eye illnesses in children and have a positive at-titude towards children and their families. This is why childhood blindness prevention programs are attempting to increase the number of pediatric ophthalmolo-gists in the developing world.

The underlying causes of blind-ness and visual impairment in in-fants and children are very differ-ent compared to those observed in adult patients, as are the over-all illness implications. Cataracts in children entail a much different clinical challenge than that typi-cally encountered in adults. The surgical treatment is more com-plex, and even following success-ful cataract removal the infant must be visually rehabilitated in order to learn to see after the pro-cedure is carried out.

To combat childhood blindness, different strategies, personnel, in-frastructure and equipment than those utilized in adult patients are required. There is also much greater urgency because of the risk of developing intractable am-blyopia specifically in children.

The causes of blindness in chil-dren vary widely from region to region. Corneal scarring occurring from childhood factors (including measles, vitamin A deficiency dis-order, trachoma, traditional eye medicines), neonatal conjuncti-vitis/ophthalmia neonatorum and trauma are more commonly seen in poorer, developing countries. In more affluent regions, lesions of the brain and the central nerv-ous system (often associated with prematurity) predominate, where-

as hereditary diseases are more prevalent in industrialized coun-tries and in the Middle East. Peri-natal factors, such as retinopathy of prematurity, are important in middle-income regions. Children are more susceptible to blindness from trauma in the developing world.

In developed countries where access to health care services is easier, the prevalence of acquired and congenital childhood blind-ness has decreased, while the prevalence of low vision associ-ated with neurological disorders has increased due to higher sur-vival rates among extremely pre-mature babies.

Vitamin A deficiency disor-der in children is caused by mal-nourishment in children in the developing world. Night blind-ness is one of the first signs of this pathology and can progress ultimately to xerophthalmia and complete blindness due to corneal scarring. Deficiency of this vita-min also lowers resistance to in-fection. The mortality rate can ex-ceed 50% in children with severe vitamin A deficiency. This disease is easily prevented by either oral or injectable supplementation of vitamin A.

Cataract is responsible for 10-20% of all childhood blindness, and the relative incidence of cata-ract as a cause of visual impair-ment in children is increasing due to the decrease of other causes in-cluding vitamin A deficiency. It affects 3 per 10,000 children but this incidence increases to 15 per 10m000 children in the develop-ing world due to poor control of perinatal infections, metabolic ill-nesses, consanguinity and trauma.

Cataracts in children are due to many different causes, the most common including inherited ten-dency, perinatal infections, met-abolic disease and trauma. Cat-aracts can manifest at birth or develop during childhood. Cata-racts that affect vision should be removed as early as possible in order to prevent interference with


a normal development of the vis-ual system.

In developing countries cata-ract surgery is not usually per-formed by surgeons with special training in pediatric cataract sur-gery and many are not performed in tertiary care centers. This leads directly to poor results follow-ing cataract surgery in children from these countries. The follow-up of these patients is often defi-cient with a subsequent difficulty in obtaining adequate visual re-habilitation. All this occurs with poor overall care of pediatric pa-tients with cataracts and explains why cataracts are still a very im-portant cause of visual impair-ment in children in the develop-ing world.

Retinopathy of prematurity is a potentially blinding pathology which is caused by the abnormal development of retinal blood ves-sels in premature infants. Most cases resolve without permanent damage to the retina, but more se-vere cases can lead to retinal de-tachment and result in blindness or severe visual impairment. The most important risk factors for the development of this illness are low birth weight and prematurity.

The prevalence of blindness due to retinopathy of prematurity varies significantly among coun-tries and depends upon the level of neonatal care (in terms of ac-cess and neonatal survival) and also upon the availability of ef-fective screening and treatment programs. It has recently become one of the most important causes of childhood blindness in middle-income countries, in which access to neonatal care has improved without the implementation of adequate screening and treatment programs for controlling the con-dition.

The population of infants who develop severe retinopathy of prematurity in highly developed countries differs from those who are affected in less well devel-oped countries where larger, more mature, infants can be severely affected.

In order to prevent visual im-pairment due to this pathology, several measures are being imple-mented, including better control of oxygen saturation levels in in-fants at risk, training of ophthal-mologists to work with neona-tologists and nurses in screening programs, development of new

forms of treatment of the illness and exploring innovative methods of screening using non-medical personnel and telemedicine.

Economic development and specific interventions are chang-ing the patterns of blindness in children all over the world. Im-proved coverage of measles im-munization and programs for the control of vitamin A deficiency and trachoma are both reducing corneal blindness in many low—income countries. As a result, cat-aracts are becoming a more im-portant cause of childhood visual impairment.

Retinopathy of prematurity re-mains a very important cause of childhood blindness with increas-ing incidence noted in less devel-oped countries.

Childhood blindness consti-tutes one of the biggest challenges in terms of prevention and treat-ment in the global health arena. In order to obtain significant results in reducing preventable childhood blindness, governments, especial-ly those in the developing world, should make this a priority and focus on the necessary resources in order to diminish preventable childhood blindness effectively.

III.5 Errori Refrattivi

DR. MARIO R. ANGI Dipartimento di Neuroscienze Università di Padova, ItaliaPresidente CBM Italia ONG Onlus

Refractive Errors Refractive errors are the first cause of preventable poor sight in the world and affect over 500 million people. 90% of the burden of uncorrected refractive errors falls on poor countries because of a lack of infrastructures, health-care personnel, instruments and optic centres. The pathogenesis of refractive defects involves

both genetic and environmental components which are currently being identified. Refractive defects can be classified into four categories: myopia, hyperopia, astigmatism and presbyopia. Myopia is caused by an excessive growth of the eyeball. The prevalence of myopia increases in families that move from a rural context to the cities and is directly correlated with study activity, a reduced exposure to sunlight, and a greater availability of food and fats. Hyperopia, which is caused by a reduced size of the eyeball, and astigmatism, are found to a greater extent

in children brought up in weak socio-economic conditions, such as the African populations of the sub-Saharan regions but also the inhabitants of poor neighbourhoods in England. Presbyopia, which is caused by an ageing of the eye’s lens, is responsible for visual disability above all in middle-low income throughout the world. The potential loss of productivity derived from the burden of uncorrected refractive errors is estimated at 28.8 milliard dollars. The cost of providing a pair of spectacles to those who need them is estimated to be 26 milliard dollars.


The elimination of poor vision caused by uncorrected refractive defects is a goal that can be pursued today through the synergic commitment of civil society, governments and the Church.

Introduzione

Desidero innanzitutto ringrazia-re il Presidente Mons. Zygmunt Zimowsky e il Segretario Mons. Jean-Marie Mupendawatu per aver dato vita a questa Conferen-za volta a favorire la conoscenza ed il dibattito intorno alle proble-matiche della lotta alla cecità evi-tabile.

Gli errori refrattivi non corret-ti rappresentano oggi uno tra i più grandi problemi di ipovisione evitabile, che si stima colpisca ol-tre mezzo miliardo di persone nel mondo. La visione sfuocata ha un impatto negativo sulla quali-tà della vita, sull’apprendimento, sul lavoro di un individuo, sulla sua famiglia, e – in ultima analisi – sulla sua comunità. La correzio-ne con occhiali appropriati degli errori refrattivi è tra gli interventi più vantaggiosi in termini di rap-porto costi/benefici nella cura de-gli occhi.

La presa di coscienza che gli errori refrattivi costituiscono la maggior causa di ipovisione al mondo è relativamente recente. Nel 2003 l’Assemblea Mondiale della Salute (WHA) ha adottato la risoluzione 56.26 Elimination of avoidable blindness per acce-lerare gli sforzi volti all’elimina-zione della cecità evitabile. Ini-zialmente le priorità identificate dal programma ‘Vision 2020’ era-no malattie come la cataratta, il tracoma, l’oncocercosi, la cecità infantile e l’ipovisione da cause mediche (maculopatia, diabete). Successivamente, studi epide-miologici hanno dimostrato che anche gli errori refrattivi non cor-retti sono una importante causa di ipovisione. La risoluzione 65.1 della WHA nel 2009 ha specifi-camente menzionato per la prima volta gli errori refrattivi. In totale, si stima che circa 100 milioni di persone potrebbero essere ipove-

denti a causa di errori refrattivi non corretti per distante, e circa 500 milioni a causa di errori re-frattivi non corretti per vicino. Il peso degli errori refrattivi non corretti grava per il 90% sui Paesi poveri, per la mancanza di infra-strutture, personale sanitario for-mato, strumenti, presidi ottici.

Gli errori refrattivi non erano stati considerati tra le cause di ri-duzione della visione nel Report dell’Organizzazione Mondia-le della Salute (OMS) nel 20041. Il loro drammatico peso viene portato alla luce solo nel Report OMS del 20082, che li riconosce come la principale causa di ipo-visione e la seconda causa di ce-cità al mondo. Come si giustifica questo? La stima della prevalenza dell’ipovisione si è enormemente estesa nel 2008 variando i crite-ri di inclusione precedentemente adottati: da “visione con la mi-glior correzione ottica” (best cor-rected) a “visione rilevata al mo-mento della visita” (presenting vision) vale a dire la visione natu-rale o con la correzione in uso, se presente. La visione rilevata alla visita fornisce realisticamente la vera prevalenza dell’ipovisione, parte della quale può essere risol-ta con la correzione ottica.

I difetti refrattivi costituiscono un grave problema di salute pub-blica. La ipovisione è correspon-sabile della povertà, in un circuito patologico che associa la manca-ta considerazione del problema (spesso i genitori sono a cono-scenza che il loro figlio è ipove-dente), i pregiudizi culturali che fanno ritenere l’uso degli occhiali un indebolimento per la vista, le difficoltà all’acquisto ed alla for-nitura di occhiali per barriere eco-nomiche e organizzative.

Prendiamo in considerazione 1) la definizione, 2) l’epidemiologia, 3) il peso economico degli errori refrattivi.

1. Definizione e classificazione degli errori refrattivi

L’occhio è un sistema ottico in cui due lenti – la cornea ed il cri-stallino – mettono a fuoco sulla retina i raggi luminosi provenienti da un oggetto posto in distanza. Si definisce errore refrattivo la con-

dizione in cui i raggi luminosi – in assenza di accomodazione – non sono messi a fuoco sulla retina, causando una visione sfuocata. Se i raggi sono focalizzati davanti al-la retina si parla di miopia, se i raggi sono focalizzati oltre la re-tina si parla di ipermetropia. Se i raggi sono messi a fuoco in più di un piano focale, a causa di una curvatura diversa della cornea nei meridiani orizzontale e vertica-le, si parla di astigmatismo. La presbiopia invece è un proble-ma causato dall’invecchiamento della lente interna dell’occhio, il cristallino, che con l’età perde la naturale elasticità e quindi la ca-pacità di accomodare. La presbio-pia colpisce indistintamente tut-te le persone a partire dall’età di 40-45 anni. Le persone con iper-metropia o emmetropia (assenza di errori refrattivi) dopo quell’e-tà hanno difficoltà nella lettura, mentre i miopi sono spesso anco-ra in grado di farlo senza corre-zione, in relazione al grado della miopia stessa.

Definiamo: MIOPIA un difetto minore o

uguale a -0.50 diottrie nei bambi-ni e -1 diottria negli adulti.

IPERMETROPIA un difetto maggiore di + 2 diottrie.

ASTIGMATISMO un difetto maggiore di 0.75 diottrie.

IPOVISIONE (visual impai-rment) una visione non corretta inferiore a 3.3/10 (6/18) nell’oc-chio migliore. Questo limite va innalzato a 5/10 (6/12) nei bambi-ni in età scolare.

2. Epidemiologia degli errori refrattivi

L’occhio umano cambia dimen-sioni e caratteristiche ottiche du-rante la crescita3. La lunghezza assiale aumenta rapidamente dai primi mesi di vita, (da 16.8 a 23.6 mm in età adulta), e la curvatura corneale diminuisce, consenten-do all’occhio di mantenere una corretta messa a fuoco. Il proces-so di crescita sincronizzata delle tre principali componenti refrat-tive dell’occhio (cornea, cristalli-no e lunghezza assiale) è chiama-to “emmetropizzazione”, e porta idealmente a un difetto refrattivo pari a zero. In ogni popolazione


una percentuale di bambini non riesce a raggiungere l’emmetro-pia, o la perde durante il periodo scolare. Il permanere di difetti re-frattivi congeniti quali l’iperme-tropia o l’astigmatismo, o la com-parsa di difetti quale la miopia sono regolati da fattori genetici ed ambientali.

A partire dagli anni ’90 stu-di epidemiologici di popolazione hanno messo in luce il fatto che il carico globale dei difetti refratti-vi di una popolazione varia a se-conda dell’età e delle regioni ge-ografiche. Il fondamentale studio “Errori refrattivi nei bambini”4 – sostenuto dall’OMS nel 2000 – ha posto a confronto i dati rilevati in campioni rappresentativi di bam-bini dai 5 ai 15 anni in tre Pae-si: Cina5, Tibet6 e Cile7. È emer-so che il 12% dei bambini cinesi aveva difetti di vista – principal-mente miopia, in Tibet il 3%, in Cile il 15%, principalmente astig-matismo elevato.

Nei primi anni di vita i fattori genetici giocano un iniziale ruo-lo predominante nel determinare i difetti refrattivi. Uno studio8 con-dotto nel 2010 su 38.000 bambi-ni rappresentativi di 8 popolazioni conferma che in India, Nepal, Sud Africa e Cile il difetto prevalente a tutte le età era una lieve ipermetro-pia, che diveniva a 15 anni miopia in meno del 20% dei casi. Al con-trario, in Malesia e Cina (rurale e urbana) a 15 anni la miopia riguar-dava più del 35% dei casi.

La prevalenza dei difetti visi-vi non è costante nel tempo, ma è influenzata da fattori ambientali. Analizziamo i più recenti contri-buti della letteratura in proposito.

2a. Miopia

La miopia rappresenta un pro-blema sociale di salute in quan-to causa ipovisione e può ave-re complicazioni sino alla cecità. Inizialmente caratterizzata nel 1600 da Keplero e Newton come un problema di focalizzazione dei raggi luminosi davanti alla retina, è stata associata dal 1800 ad una eccessiva crescita il lunghezza del globo oculare. Numerose ipo-tesi sono state avanzate negli anni per capire se prevalgono in questa crescita fattori genetici o ambien-tali quali la scolarità e il lavoro

da vicino. Esperimenti su modelli animali hanno confermato che la crescita dell’occhio è sicuramente influenzata dalla qualità dell’im-magine retinica. Chi studia ha un maggior rischio di miopia a causa della sfocatura delle immagini in-dotta sulla retina dalla vicinanza del libro.

La prevalenza di miopia è si-gnificativamente più alta in aree urbane rispetto ad aree rurali. Questo emerge con chiarezza in studi condotti in Cina.

Fan9 confronta la prevalenza di miopia rilevata in bambini di asilo di Hong Kong nel 1997 e nel 2007, e trova un aumento dal 2.3% al 6.3%. Shih10 trova una progressione della miopia in ma-schi e femmine di 0.24/0.31 diot-trie per anno in ambito rurale, 0.43 e 0.50 diottre per anno in ambito urbano. Lam11 confronta la preva-lenza di miopia rilevata nel 1990 e nel 2010 a Hong Kong in bam-bini, e pur trovando percentuali sostanzialmente stabili di miopia nel tempo (25% contro il 18% a 6 anni, 64% contro 61% a 12 anni) conferma in città una prevalenza di miopia più che doppia rispetto all’area rurale. Zhang12 trova una correlazione positiva tra presenza di miopia, densità di popolazione e lavoro da vicino. Lim13 in bam-bini di 12 anni di Singapore trova una associazione tra miopia, mag-gior lunghezza assiale del globo e dieta più ricca di acidi grassi satu-ri e colesterolo. Wu14 studia l’in-fluenza di attività all’aperto sullo sviluppo della miopia in bambini di 7-12 anni, e trova una signifi-cativa associazione diretta tra au-mento della miopia, anni di studio e familiarità, mentre trova una as-sociazione inversa tra miopia ed attività all’aperto.

La tendenza si conferma an-che in altre popolazioni. In India a Hyderabad15 la prevalenza di miopia risulta significativamente maggiore in bambini di età scola-re in ambito urbano (51%) rispet-to al rurale (17%). Uno studio di prevalenza condotto negli Stati Uniti in persone dai 12 ai 54 an-ni mostra negli ultimi 30 anni un aumento della miopia, passata dal 25% nel 1972 al 41.6% nel 2004. Le stime di prevalenza della mio-pia variano anche in relazione al-la razza: i neri sono passati dal

13% al 33%, i bianchi dal 26.3% al 43%16. Rudnicka17 conferma una differenza etnica sulla preva-lenza di miopia in bambini di 11 anni di scuole inglesi. La preva-lenza variava dal 25% negli asia-tici al 10% negli africani caraibi-ci al 3.2% negli europei bianchi. A parità di ambiente geografico e di quantità di studio, differenze di prevalenza della miopia sono cor-relate a differenze etniche nella grandezza del globo oculare. La prevalenza della miopia massima (78.4%) è stata trovata in bambini cinesi di 15 anni di città18, e mini-ma (1.2%) in bambini nepalesi di 5-15 anni in area rurale6.

Questi dati in qualche mo-do rappresentano un ritorno al-le indicazioni di “igiene visiva” dei primi oculisti dell’ottocento, quando si raccomandava di avere una buona illuminazione possibil-mente naturale, mantenere la po-sizione eretta studiando ed evitare l’inclinazione del capo in avanti che era creduta produrre “conge-stione oculare” e distensione del globo19.

2b. Astigmatismo e ipermetropia

L’astigmatismo è un difetto re-frattivo dovuto alla diversa curva-tura dei principali meridiani cor-neali. È presente alla nascita, e di norma nei primi 18 mesi di vita si riduce spontaneamente20. Se è di origine genetica, permane per tutta la vita. L’eredità del difetto è di tipo autosomico dominante21, e presenta marcate differenze etni-che. In Sud America, lungo la cor-digliera andina, la prevalenza di astigmatimo elevato > 2 diottrie colpisce dal 12 al 15% dei bam-bini7. Prevalenze elevate di astig-matismo sono segnalate anche in altre popolazioni. Fozailoff22 con-duce uno studio in bambini afro-americani e ispanici dai 6 ai 72 mesi in California, e trova una prevalenza di astigmatismo mag-giore nei bambini ispanici (16.8 vs 12.7%), con una tendenza alla riduzione con l’età. Rezvan23 stu-dia bambini dai 6 ai 17 anni nel nord Iran e trova l’11.5% di casi con astigmatismo, contro il 4.3% di miopia ed il 5.4% di ipermetro-pia. La presenza di astigmatismo si associa ad un rischio 4.6 volte più alto di sviluppare una miopia,


ed una capacità visiva più bassa24. Oltre all’influenza genetica, so-no state trovate associazioni tra la deprivazione socio-economica e la presenza di ipermetropia ed astigmatismo nella popolazione. L’indice di deprivazioni multiple, ottenuto misurando diversi cam-pi socio-economici e correlando-li con la località dove è vissuto il bambino ha mostrato in bambini inglesi una associazione lineare tra lunghezza assiale più corta, ed astigmatismo più elevato25.

Correla con queste osservazio-ni lo studio di prevalenza dei di-fetti refrattivi condotto in bam-bini dai 6 ai 16 anni in Burkina Faso. La miopia è stata trovata solo nel 2.5% dei casi, l’iperme-tropia nel 17.1% e l’astigmatismo nell’11.7% dei casi26.

In Marocco, uno studio di bam-bini della stessa età ha mostra-to dati simili: miopia 6.1%, iper-metropia 18.3%, astigmatismo 23.5%27.

In conclusione, gli studi più re-centi mostrano l’aumento della prevalenza di miopia nei bambi-ni le cui famiglie si spostano dal contesto rurale verso la città. La crescita della lunghezza assiale causa di miopia correla diretta-mente con l’attività di studio, la ridotta esposizione alla luce so-lare, la maggiore disponibilità di cibo e di grassi. Al contrario, una ridotta dimensione del globo ocu-lare ed un astigmatismo più ele-vato si trova nei bambini in con-dizioni socio-economiche più deboli, come le popolazioni afri-cane nelle regioni sub-sahariane, ma anche gli abitanti dei quartieri poveri in Inghilterra.

2c. Presbiopia

La presbiopia, che necessita di occhiali correttivi per vicino, è stata a lungo considerata “non così importante” a causa della presunzione che gli occhiali da lettura sono generalmente poco costosi e facilmente disponibili. Tale difetto non è stato neppure inserito nella attuale definizione di ipovisione. Si è “dimenticato” di considerare un problema che ri-guarda oltre 1 miliardo di persone nel mondo (2005) delle quali 517 milioni (49%) non hanno nessuna correzione o una correzione ina-

deguata28. Il WHO Bullettin in-dica la presbiopia come un pro-blema di salute significativo, con potenziali conseguenze negative sulla produttività e qualità di vi-ta dei soggetti affetti. La cresci-ta della popolazione mondiale e l’aumento dell’età proiettano que-sta stima ulteriormente in alto. Il peso di questa situazione ricade nel 90% sui Paesi poveri29.

Marmamula30 riporta i risultati di uno studio di popolazione sul-la prevalenza dei difetti visivi non corretti condotto il Andhra Pra-desh, India. Il 67% dei soggetti sopra i 35 anni presentava proble-mi di presbiopia, la copertura con occhiali era del 19% . In un ulte-riore studio31 condotto in comuni-tà costiere di pescatori in India la correzione della presbiopia riguar-dava solo l’11% dei soggetti. Uno studio condotto in Nigeria32 ha mostrato la presbiopia come più comune errore refrattivo (35%) seguita dall’astigmatismo (19.7%)e dall’ipermetropia (22.7%). Solo il 4.9% aveva miopia. La corre-zione con lenti ha ridotto l’ipovi-sione del 90% nella comunità. In uno studio condotto a Zanzibar33 la prevalenza di presbiopia in pa-zienti sopra i 50 anni era dell’89%: solo il 17.6% aveva occhiali. Al follow-up dopo 6 mesi dalla for-nitura di una correzione il 93% aveva ancora in uso gli occhiali e dichiarava significativamente mi-gliorata la propria qualità di vita.

3. Peso economico degli errori refrattivi

Uno studio sulla ineguaglian-za della distribuzione della salute oculare prende in considerazione la somma di DALYs (disability-adjusted life years) relativi a ca-taratta, tracoma, glaucoma, deficit di vitamina A, errori refrattivi e maculopatia. Il carico globale del-le malattie oculari è stato stimato di 61,4 milioni di DALYs, il 4% del totale34.

Gli errori refrattivi forniscono il maggior contributo alla disabilità visiva nelle classi a medio-basso reddito in tutto il mondo. La po-tenziale perdita di produttività che risulta dal carico degli errori refrattivi non corretti è stimata in 268.8 miliardi di dollari29. Il costo

per provvedere a tutte le persone che ne hanno bisogno un paio di occhiali prevedendo un ricambio ogni 3 anni al prezzo di 150 dolla-ri è stato calcolato in 26 miliardi: dieci volte meno del danno eco-nomico teoricamente ipotizzato. In realtà, molti beni di consumo – inclusi gli occhiali – non rappre-sentano spese sostenibili per i set-tori più poveri di ogni società. A sostegno di questa constatazione, l’ipovisione e la cecità colpisco-no in modo sproporzionatamente maggiore persone povere senza istruzione e le donne.

La scarsa copertura di servizi re-frattivi è la regola in aree rurali. I seguenti fattori sono chiamati in causa: costi, mancata percezione del bisogno, mancanza di accesso ai servizi. La domanda e la percen-tuale d’uso di occhiali è ulterior-mente ridotta da pregiudizi socia-li o estetici, dal preconcetto che l’uso degli occhiali indebolisca la vista, o dalla semplice ignoranza dell’esistenza di un difetto di vista.

Conclusioni

Abbiamo quindi oggi se si può dire “messo a fuoco” meglio il quadro complessivo. L’attuale scenario preoccupante può mi-gliorare rapidamente attraverso una serie di iniziative coordina-te, come è già avvenuto nei primi 10 anni della campagna ‘Vision 2020’ per altre cause di cecità ed ipovisione, quali la cataratta ed il tracoma.

C’è bisogno di occhiali prefab-bricati a basso costo, di produzio-ne locale di occhiali, di sviluppo di nuovi strumenti per la misura della refrazione che siano eco-nomici, solidi, usabili a distanza, possibilmente senza l’uso di col-lirio cicloplegico.

L’evoluzione della tecnologia ci aiuta. La misura degli errori refrattivi si faceva con lo schia-scopio, piccolo strumento che ri-chiede una stima soggettiva del difetto, e che comporta difficol-tà nella misura dell’astigmatismo e dei difetti elevati. Dal 1980 lo schiascopio è stato affiancato e progressivamente sostituito da re-frattometri automatici, strumen-ti che forniscono una misura del difetto refrattivo. I refrattometri


avevano ed hanno il difetto di es-sere costosi, ingombranti e dipen-denti dall’energia elettrica; nel 1995 è stato introdotto il primo refrattometro portatile a batteria. Alla fine degli anni ’80 sono stati introdotti nuovi refrattometri bi-noculari, più adatti allo studio dei difetti visivi pediatrici in quanto utilizzati alla distanza di 1 metro; questi strumenti saranno presto disponibili a batteria, portatili e quindi più adatti all’uso anche in contesti rurali.

Con i nuovi mezzi che abbiamo a disposizione si deve formare più personale addestrato per lo scree-ning visivo, per la cura degli oc-chi, per la misura della refrazione e per la fabbricazione / distribu-zione di occhiali.

I Governi, le Organizzazioni in-ternazionali, le Associazioni pro-fessionali, l’Industria Ottica, la Chiesa devono mette in campo le loro energie. Eliminare l’ipovisio-ne da difetti refrattivi non corretti è la sfida che vogliamo raccoglie-re e vincere!.

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